1. Field of the Invention
The present invention is broadly concerned with apparatus and methods for area decontamination and is of particular utility for emergency situations where a given area must be at least partially and rapidly decontaminated. More particularly, the invention is concerned with such devices and methods which include a container that is or can be pressurized containing sprayable mixture therein including reactive metal oxide and/or metal hydroxide particles (e.g., MgO) and having a selectively operable spray nozzle assembly coupled with the container. The invention finds particular utility for destroying or chemisorbing a variety of chemical, biological and/or hazardous agents, especially chemical/biological warfare agents.
2. Description of the Prior Art
Governments around the world have become increasingly concerned about the effects of chemical and/or biological warfare agents and other types of hazardous substances, particularly in light of the recent rise in terrorism. The potentially catastrophic results which could ensue in high density population centers subjected to such agents are well known to disaster experts. While a number of proposals have been adopted for dealing with warfare agents and similar substances, in general these deal with massive decontamination or cleanup efforts. However, it is contemplated that, in many instances, there will be a need for immediate, at least partial decontamination over restricted areas in order to minimize the risk to affected populations.
There are currently two general types of decontamination methods for biological agents, namely chemical disinfection and physical decontamination. Chemical disinfectants such as hypochlorite solutions are useful but are corrosive to most metals and fabrics, and to human skin. Liquid-like foam disinfectants have also been used, and generally require water and pressurized gases for efficient application. Physical decontamination usually involves dry heat up to 160° C. for 2 hours or steam or super-heated steam for about 20 minutes. Sometimes UV light can be used effectively, but it is difficult to implement in actual practice. Techniques used for decontamination of areas subjected to chemical warfare agents are more varied, and depend principally upon the nature of the agent in question.
U.S. Pat. No. 5,914,436 describes methods for the destruction of unwanted compounds such as chlorocarbons, chlorofluorocarbons and PCBs, making use of metal oxide composites as adsorbents. Also, U.S. Pat. No. 6,057,488 describes the use of metal oxide nanoparticles for the destructive adsorption of biological and chemical contaminants, including biological and chemical warfare agents. However, these references do not describe techniques for the rapid use of metal oxides in emergency-type situations.
It is known that magnesium oxide and other similar oxides can be produced by varying techniques. In the case of MgO, very fine nanometer sized particles are best produced using aerogel preparation methods (and thus is often referred to “AP—MgO”) such as those described by Utamapanya et al., Chem. Mater., 3:175-181 (1991). A specific example of AP—MgO preparation is set forth in Example 1 of the aforementioned U.S. Pat. No. 6,057,488. MgO particles can also be prepared by conventional methods (and is hence often referred to as “CP—MgO”), involving boiling commercially available MgO followed by microwave drying thereof and dehydration under vacuum at high temperature, e.g., 500° C.